Date of Award

5-1-2014

Degree Type

Thesis

Degree Name

Master of Science

Department

Engineering

First Advisor

Hani H. Titi

Committee Members

Rani El-Hajjar, Yue Liu

Keywords

Aashtoware, Mepdg, Osow, Wisdot

Abstract

This study researched the impacts of overweight permit vehicle traffic on flexible pavement performance in Wisconsin using field investigations and AASHTOWare MEPDG analyses. A database of Oversize/Overweight (OSOW) single trip permit truck records was analyzed and provided a network of Wisconsin corridors heavily trafficked by OSOW trucks. Four Wisconsin state trunk highways were selected for investigation due to a high level of OSOW truck traffic. The research included traffic counts to confirm the levels of truck traffic on these segments and to verify the high numbers of permits issued for OSOW trucks. Furthermore, the field work included the identification and quantification of pavement surface distresses by executing visual distress surveys allowing for the current pavement surface conditions to be rated using the pavement condition index.

Comprehensive analyses were conducted to evaluate pavement performance due to normal traffic loads as well as normal traffic loads plus the OSOW truck traffic loads. The use of AASHTOWare MEPDG analyses presented a potential methodology for determining the proportion of pavement deterioration attributable to OSOW truck traffic. OSOW axle load distributions were integrated with baseline truck traffic levels to develop axle load spectra and other traffic input parameters for the MEPDG analysis.

Visual distress surveys conducted at the selected segments of state trunk highways (STH) 140, 11, and 26 rated the pavement surface conditions as serious to poor, ranging from a PCI value of 13 on STH 140 to a PCI value of 52 on STH 11. Across these three segments, the maximum measured rutting depth along the outer wheel paths ranged from 0.82 in to 1.25 in, which exceeded WisDOT's threshold for acceptable rutting of 0.50 in. Only the segment of STH 23 exhibited a fair pavement surface condition due to PCI values of 63 and 66 in the two lanes, with a maximum rutting depth of 0.50 in. The generally poor pavement conditions across the sampled segments included significant pavement surface damage and distresses such as rutting, longitudinal and transverse cracking, significant fatigue cracking, and potholes.

The predicted total pavement deterioration levels from the AASHTOWare MEPDG software were generally consistent with the levels of deterioration observed during the site investigations. However, the proportion of pavement damage and deterioration attributable to OSOW truck traffic was predicted to be fairly insignificant, with most distress indices showing relative increases of approximately 0.5% to 4%, with a few outliers. The addition of OSOW truck traffic to the baseline truck traffic volumes resulted in a small increase in the amount of pavement damage, rutting depths, and loss of ride quality compared with the predicted deterioration levels due to only the baseline traffic.

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